Catalog
of Long Term Research Conducted by the Northeastern Research Station

Catalog #50

Title:

Effect of Deer Population
Levels on Natural Regeneration of Allegheny Hardwoods

Objective:

1) To determine the average deer density which will allow
natural regeneration of desirable Allegheny hardwood timber
species at adequate stocking levels in stands managed under
even-age silviculture.
2) To determine the effects of known herd-size on browse-use
over a range of regeneration conditions in Allegheny Plateau
cherry-maple stands.
3) To determine if deer density impacts songbird, small mammal,
shrub and herb communities.

Year Established:

1978-1980

Year Completed:

1991

Site Description:

Warren, McKean, Forest, Elk, and Potter counties in the Allegheny
Plateau of Northwestern Pennsylvania. Hardwood stands in the
large pole-small sawtimber size class, managed on a 100-year
rotation with a 10-year cutting cycle. The 4 sites (replications)
represent the following 4 levels of regeneration potential:
a) poor - less than 30% of the sample quadrats adequately stocked
with desirable tree seedlings.
b) below average - between 30% and 50% of the sample quadrats
adequately stocked with desirable tree seedlings.
c) above average - between 50% and 70% of the sample quadrats
adequately stocked with desirable tree seedlings.
d) good - greater than 70% of the sample quadrats adequately
stocked with desirable tree seedlings.
Desirable commercial woody species typical of Allegheny hardwoods
are sugar maple, red maple, yellow-poplar, white ash, black
cherry, and cucumber. Overstory composition may also include
other commercial species such as beech, eastern hemlock, white
pine, birch, basswood, aspen, butternut, and in transition stands,
oak and hickory. Undesirable woody seedlings are judged on the
basis of their value as deer forage, of their commercial value,
and of their competitive influence on higher value species.
The two most prominent species are beech and striped maple.
At least one site contains an understory dense with plants that
interfere with desirable regeneration such as ferns, grasses,
and sedges.

Statistical Design:

Randomized block design with stratified, systematic sampling
from a random start. 4 160-acre fenced blocks, each cross-fenced
to form 4 plots; 1 of 64 acres and 3 of 32 acres are established
and replicated at 4 separate locations across 5 counties on
northwestern PA's Allegheny Plateau. 8 deer were introduced
into each block at a rate of 1 deer per 64 acres, and 1, 2,
and 4 deer in the 3 32-acre plots, thus simulating 10, 20, 40,
and 80 deer per square mile.

Each fenced plot contains a mixture of clear-cut, thinned
and uncut stands along with selected openings resulting from
haul roads and log-landings. The 4 blocks range in regeneration
potential (for desirables) from poor (30% regeneration stocking)
to excellent (70% regeneration stocking). Seedling responses
under the various deer densities were compared using permanently
marked fenced 6' radius sample plots measured just before
deer introduction, during the 5th year, and during the 10th
year after establishment.

In the 11th year of study, evaluation of response of other
communities to deer density was added. Songbirds were censured
at fixed census locations within each silvicultural treatment
within each deer density. Small mammals were censured by live-trapping
on 50-trap grids within each of the deer density x structural
treatments. Herbs and shrubs were tallied by estimating percent
ground cover, by species in May-June, within 30 milacre plots,
located randomly within each deer density x silvicultural
treatment.

Likelihood of Locating Study Areas:

100%

Experimental Treatments:

The following is representative of the acreages treated silviculturally
for each plot size:

The following is representative of the acreages treated with
deer densities per plot:

Plot Size

No. of Deer

Equiv. Deer/Square Mile

Actual Density

64 acres
32 acres
32 acres
32 acres total=160

1
1
2
4

10
20
40
80

10
20
38
64

Sampling Methods:

Seedling counts made during tallies of regeneration plots
(0.001 acre each) were by species and height classes: <0.1',
<0.5' to 1', <1', 1' to 3', 3' to 5', <5'. Herbaceous
cover was measured in only the regeneration plots. Not all regeneration
plots were measured at every tally and height classes varied.

Plots were located away from fence lines or open trails to
avoid exposing features to abnormal use by the study animals
and potential erroneous data. Data-entry into computer was 100%
cross checked with field sheets.

Data Storage:

Raw data by plot reside on DG and tally sheets are kept with
written instructions and detailed maps to each stand. Annually,
the raw data are transformed using the REGEN1 program in DG
Info. System. Summarized data by plot and by stand reside in
a DG-based program that can output to ASCII text files.